I. Field of the Invention
This invention relates to timekeeping and, more particularly, to the use of digital time displays for general purpose timekeeping, as is the practice of many individuals in performing their daily activities while watching and keeping track of the time.
II. Description of the Prior Art
Quadribalanced digital time displays are described in U.S. Pat. No. 4,271,497, the disclosure of which is incorporated herein by reference. Those displays comprise centrally positioned hour digits flanked on the right by increasing minute digits displayed in upper and lower positions relative to current hour digits during the first and second quarter hours. Thereafter, next hour digits are flanked on the left by decreasing minute digits displayed in lower and upper positions during the third and fourth quarter hours. In this way, the four quarter hours are precisely defined, balanced and visually differentiated, while elapsed and future time are viewed during the respective first and second halves of each hour.
In addition, a pair of multiple digital display elements, each comprising seven elements arranged in a numeral xe2x80x9c8xe2x80x9d pattern, is located below the centrally positioned hour digits in the above-described displays. That pair is operated to display 0-59 incrementing seconds during each rising minute digit of the first half hour, and to display 59-0 decrementing seconds during each falling minute digit of the second half hour.
III. Recognition of Problems in the Prior Art
The present applicant has recognized certain problems in the prior art.
The specification of U.S. Pat. No. 4,271,497 does not specifically describe and portray how the setting or resetting of the display of hours is to be synchronized with the current AM or PM cycle of any 24-hour day. Generally, conventional digital displays activate a display of an AM or PM indicator, with or without flashing, when the current hour display is activated by flashing to signal that it is capable of being set or reset to another value. Such setting or resetting is usually accomplished by operating a control, typically a push button, which scrolls the existing hour value forward, incrementally or continuously, through a set of values from 1 through 12 to permit stopping at any desired new value.
Thus, and for example, when a wristwatch or clock is to be reset back one hour, in order to switch from daylight savings to standard time, it is necessary to scroll through eleven intermediate hour values to reach the desired new hour, since the values scroll unidirectionally only in the forward direction. Similarly, to set or reset an hour display due to traveling through one or more different time zones, or because an alarm time needs to be set, scrolling through multiple hour values is again often required to reach the desired hour value.
In addition, these setting/resetting procedures involve the fact that not only does the hour value have to be correct, but it also must be synchronized to the proper AM or PM cycle of the 24-hour day. Usually, the activated AM or PM indicator can only be changed by scrolling the hour values sufficiently forward until the indicator switches from one cycle to the other, thus enabling selection of the correct AM or PM time cycle, as well as the correct hour. Accordingly, setting and resetting of digital hour values is complicated and sometimes confusing in view of the requirements imposed on the viewer by the above-described conventional procedures.
Finally, in some embodiments of enhanced quadribalanced displays disclosed in the above-cited applications, Ser. Nos. 09/679,864 and 09/619,368, there is space only in the top portions of the displays to locate and display the AM or PM indicators, which interferes with locating a symmetrically positioned alarm indicator or icon in the same space. This is also often true of conventional digital time displays which operate solely by showing 59 minutes of incremental elapsed minutes on the right side of an existing hour during each hourly cycle.
The present invention is based on the realization that the foregoing problems can be substantially alleviated or overcome by modifying the digital display elements that display seconds in a digital time display, such that they also perform a second function of displaying AM/PM indicators whenever the hours in the display have to be set or reset to a different value. By creating such dual functions for these display elements, the space otherwise occupied in the display by conventional separately located AM/PM indicators is freed for use in other ways, for example, day or month names or dates, or alarm indicators or icons. This has especially important value for the enhanced quadribalanced displays of Ser. Nos. 09/679,864 and 09/619,368 because there, seconds are displayed in a special location below centrally positioned hour displays. The capability of such elements to also provide AM/PM indicators enables using the larger empty space in the top portion of the display for presentation of other information such as, for example, symmetrically located alarm indicators, as will be illustrated and further described hereafter.